1. Pete Johnston, Eduserv pete.johnston@eduserv.org.uk http://www.eduserv.org.uk/research/ 16 October 2009 Relationship between foaf:maker & dc:creator/dcterms:creator DCMI Usage Board, DC-2009, Seoul, Korea

2. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea2 Background: UsingDublinCoreCreator (Content from July 2003 onwards….) Discusses historical ambiguity in (ab)use of dc:creator Value as –Name (literal) –Agent –List of names (literals) –List of Agents FOAF community resolution: –Coined foaf:maker (range = foaf:Agent) –Recommended using dc:creator (only) with literal value –Rule for inferring dc:creator triple from foaf:maker/foaf:name triples http://wiki.foaf-project.org/w/UsingDublinCoreCreator

3. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea3 FOAF: foaf:maker Property foaf:maker http://xmlns.com/foaf/0.1/maker An agent that made this thing. Domain: owl:Thing Range: foaf:Agent

4. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea4 Guidelines The foaf:maker property relates something to a foaf:Agent that foaf:made it. As such it is an inverse of the foaf:made property.foaf:makerfoaf:Agentfoaf:made The foaf:name (or other rdfs:label) of the foaf:maker of something can be described as the dc:creator of that thing.foaf:namefoaf:maker For example, if the thing named by the URI http://rdfweb.org/people/danbri/ has a foaf:maker that is a foaf:Person whose foaf:name is 'Dan Brickley', we can conclude that http://rdfweb.org/people/danbri/ has a dc:creator of 'Dan Brickley'.foaf:maker foaf:Personfoaf:name FOAF descriptions are encouraged to use dc:creator only for simple textual names, and to use foaf:maker to indicate creators, rather than risk confusing creators with their names. This follows most Dublin Core usage. See UsingDublinCoreCreator for details.foaf:maker UsingDublinCoreCreator http://xmlns.com/foaf/spec/#term_maker

5. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea5 DCMI: dcterms:creator January 2008: DCMI coins new property dcterms:creator –Range: dcterms:Agent October 2009(?): DCMI deletes part of comment for dcterms:creator saying –Typically, the name of a Creator should be used to indicate the entity. Essentially, foaf:maker = dcterms:creator –But currently not stated formally

6. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea6 Suggestion (1) Dan wants FOAF to say that foaf:maker is a sub-property of dcterms:creator and asks whether DCMI could make a reciprocal claim. –https://www.jiscmail.ac.uk/cgi- bin/webadmin?A2=ind0906&L=DC- USAGE&P=14469https://www.jiscmail.ac.uk/cgi- bin/webadmin?A2=ind0906&L=DC- USAGE&P=14469 i.e. –FOAF says foaf:maker rdfs:subPropertyOf dcterms:creator. –DCMI says dcterms:creator rdfs:subPropertyOf foaf:maker.

7. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea7 Suggestion (1): Discussion foaf:maker rdfs:subPropertyOf dcterms:creator. Means that –Thing:A foaf:maker Agent:P. => Thing:A dcterms:creator Agent:P. –And (from rdfs:range) Agent:P a dcterms:Agent. –And (from rdfs:subPropertyOf) Thing:A dcterms:contributor Agent:P. Thing:A dc:contributor Agent:P. Thing:A dc:creator Agent:P.

8. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea8 Suggestion (1): Discussion dcterms:creator rdfs:subPropertyOf foaf:maker. Means that –Thing:B dcterms:creator Agent:Q. => Thing:B foaf:maker Agent:Q. –And (from rdfs:range) Agent:Q a foaf:Agent. –And (from rdfs:domain) Thing:B a owl:Thing. –And (from owl:inverseOf) Agent:Q foaf:made Thing:B.

9. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea9 Suggestion (2) FOAF changes the guideline for foaf:maker to remove the text encouraging the use of dc:creator with literal values? N.B. following suggestion (1) –Thing:A foaf:maker Agent:P. –=> Thing:A dc:creator Agent:P.

10. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea10 Issues Semantic –Generally, mutual subproperty assertions not a problem in RDFS –For these two properties, mutual subproperty assertions generate no unwanted entailments (AFAICT!) –Not necessary for FOAF & DCMI to publish assertions at exactly the same time Social –Setting a precedent? –Will we be asked to make other such assertions? –What are criteria for deciding to consider such requests? Are there other assertions we might make re terms in other vocabularies? e.g. (examples only!) –dcterms:type rdfs:subPropertyOf rdf:type. –dcterms:title rdfs:subPropertyOf rdfs:label.

11. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea11 Proposal (provisional pending discussion) For the property dcterms:creator –add the assertion that dcterms:creator rdfs:subPropertyOf foaf:maker.

12. 16 October 2009DCMI Usage Board, DC-2009, Seoul, Korea12 Relationship between foaf:maker & dc:creator/dcterms:creator Title slide photo Korean Folk Drumming by Flickr user paul walk See http://www.flickr.com/photos/paulwalk/4011459348// Made available under CC Attribution 2.0 licensehttp://www.flickr.com/photos/paulwalk/4011459348//CC Attribution

13. Pete Johnston, Eduserv pete.johnston@eduserv.org.uk http://www.eduserv.org.uk/research/ 16 October 2009 Relationship between foaf:maker & dc:creator/dcterms:creator DCMI Usage Board, DC-2009, Seoul, Korea